[Population of triplet-excited states of tryptophanyls and tyrosyls in proteins]

The relative limiting concentrations of triplet excited states of tryptophan and tyrosine residues have been measured by the ESR method. The magnitude of limiting concentration of the tryptophan and tyrosine residues T1-states does not vary to fit their numbers in some proteins. A limitation on the concentration of T1-states is accounted for by the fact that in protein molecules there occurs the radiationless excitation energy transfer of chromophores on residues in the triplet state.